| A Waving Cold Front and Minus 47
14/4/2000 Clyve Herbert, Jane ONeill |
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Thursday 13th was a bit odd. You don't often see drizzle and humidity around 70% in a northerly airstream over southern Victoria. Such was the moisture loading of a pre-frontal northerly after several days of rain over northern Victoria, southern NSW & eastern South Australia. All day the dividing range was capped in low Cu & drizzle. It was one of those rare times when one could imagine what a northerly airstream would be like if a huge sea existed to the north of the divide - although apparently many thousands of years ago this area was a large sea. With all this moisture and an approaching cold front due on Friday 14th April (does this date bring something to mind for Sydneysiders?), things looked promising. Overnight Thursday and early Friday as the front approached, something started to happen. An unanalysed wave low developed near Mt Gambier along the cold front. This enhanced uplift over northern and mountain areas of Victoria producing falls of rain between 20 and 70mm. The small wave moved into central Victoria early Friday. 10am soundings showed 300hPa temperatures at -42.1C which decreased to -47C by the 10pm sounding - not bad!! and 500hPa temperatures at -14C. As the mid and upper level cloud band drifted slowly to the east, a clear area developed over west central Victoria, and sunshine soon got to work, driving deep moist cumulus and showers by midday over the west central region.
Looking WSW from Kew towards the city
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I left Geelong for Melbourne at around 2.15pm. It was handy having my work sign on time co-ordinating with a large multicell north of Geelong. By 2.45pm I was approaching a mature Cb south west of Werribee with the Princes Highway bisecting the central core (handy!!). Looking SW from Kew towards Werribee -
Clyve's enjoying himself no doubt !!! I rang Jane ONeill for a radar intensity. She reported that it was showing 40-100mm/hr with a small area of 100+mm/hr. The rainshaft certainly looked impressive with a developing foot on the western side, and a nice flanking line to the cloud as well. I drove through the central core of the storm and had to slow to less than 20kmh with my view almost totally obliterated. This was a serious carwasher!! Torrential rain continued for about 5 minutes and I reported the incident to the BoM who confirmed the 100+ radar return. I then cleared the storm line and barely over a distance of 200metres went from wet to dry. The flanking line to the west looked very impressive with lowerings and mid air scud. I drove to Laverton, pulled over and took 20 frames or so.
Eventually this multicell rained out and dissipated, however these congesting cumulus continued to make their appearance around the Melbourne metro area for the rest of the afternoon (despite the intensity of this rain storm, at no time did I detect any lightning, which was indeed a surprise, as it threw up a very nice glaciated anvil).
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Courtesy - Bureau of Meteorology
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| Later in the
afternoon, another multicell moved from Geelong across the Bellarine Peninsula and across
southern Port Phillip Bay to the Mornington Peninsula. This system also looked very
impressive with a flanking line and lowerings, however these 2 systems were only the
support act to what was to appear in the Northeastern suburbs of Melbourne later in the
afternoon.
Looking S from Kew towards Port
Phillip Bay later in the afternoon At around 4.30pm a trough moved through the Melbourne CBD. This was accompanied by a line of deep congesting cumulus with low bases. They looked very impressive! As the trough edged north/northeastwards into the northern suburbs, this line intensified with a wall-like cloud appearing to the north east of Melbourne. I again rang Jane ONeill and suggested she keep an eye on this system which would have been 5kms north of her work location....from this point I'll hand you over to Jane for her description.......... |
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See the cell on its own just north of
Port Phillip Bay!!
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| After an excited
phonecall from Clyve about this developing system to the north, and grabbing the camera
and my running shoes I got up onto the roof again! (that's where I'd been on and off
through the day anyway after discovering a waterfall down the inside of the office wall at
7.30am courtesy of a rotting gutter). I don't know why the plumber couldn't
understand why I was so happy to be up on the roof...his comment while scratching his head
was "I've never found a woman so happy to run around on a corrugated iron roof.
before...." I took a few quick shots of the trough line to the west over the city and also a multicell to the south moving across the Bay before looking to the north. At this stage, the cell that Clyve was talking about wasn't easily seen through the middle level cloud (MLC) even though I knew its location though radar, so I went back down to ground level & kept an eye on the radar while I finished up at work for the week.
Looking N (left) and E (right) through
the MLC By 6pm, I'd been backwards and forwards to the back door (which faces north) a few times & the cell went red on radar - printer & computer went off & I was out the door and up the hill in less than 5 minutes to be greeted by an absolutely stunning sight.....Cb's to the north (the lightning active cell that had already gone severe), the east, and the southeast (which ultimately became lightning active and developed the guster). The rain curtain out of the Cb to the north was a pinkish-yellowish-brown in the setting sun, and the anvil was glowing from gold to red in the setting sun. Clyve rang to tell me about the clear air lightning he'd seen from the anvil with a moon coming out from behind it (......what else would you want in a photo? except a camera focussed on this at this particular second....) I was videoing the rain shaft to the western end of the cell and a cone lowering to the east when I managed to get *the* shot of the day at 18:08 - rain shaft, cg & a cone lowering all in one frame!!! The cone lowering persisted for close to 5 minutes. |
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Looking E from the hill in Kew |
Looking NE from the hill in Kew |
Looking NE (left) from the hill in Kew |
 Looking
E from the hill in Kew |
| Unlike the
afternoon's storms which had no lightning, or not much - these ones were very lightning
active & produced some very heavy rainfall totals. Claire McDonald reported very heavy
rain with thunder in Greensborough - a total of 13mm while a very frustrated Andrew
McDonald sat on a train unable to see but getting progress reports from Clyve, Claire
& me.
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Courtesy - James Cook University |
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Courtesy - Bureau of Meteorology |
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Courtesy - University of Wyoming |
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| Thanks go to the
following organisations and individuals for the information presented:- Bureau of Meteorology University of Wyoming James Cook University CSIRO Marine Research Kim Badcock |
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